The present invention relates to vehicle seats.
More particularly, the invention relates to a vehicle seat comprising a seat proper and a seat back pivotally mounted on the seat proper to pivot about a transverse horizontal axis, said seat proper being made up of a rigid framework which carries flexible padding having a bearing face adapted to support a user sitting on the seat, the seat proper further including a support member that is substantially rigid, that is disposed under the bearing face of the padding, and that is mounted to move relative to the framework of the seat proper so that it can move at least vertically, said support member being adapted to form an abutment preventing the user of the seat from plunging into the padding downwards and forwards when the seat is subjected to high forward deceleration.
Document U.S. Pat. No. 5,125,472 describes a seat of this type, in which the support member is moved upwards by an automatic actuator device when the vehicle in which the seat is installed is subjected to an accident.
However, that type of seat suffers from the drawback that, even though the support member rises into its active position extremely rapidly, the user of the seat starts to plunge into the padding of the seat proper while said member is rising, which reduces the effectiveness of that support member.
That drawback is even more significant when the back of the seat is tilted backwards to a large extent, because such a reclined position increases the risk of the user of the seat being thrown forwards by slipping under the lap segment of the seatbelt that the user is wearing, and by plunging at least partially into the padding of the seat proper.
A particular object of the present invention is to mitigate those drawbacks.
To this end, in the invention, a seat of the type in question further comprises a coupling device connected to the support member and adapted to raise said support member when the seat back pivots backwards, and to lower the support member when the seat back pivots forwards.
By means of these provisions, the support member may be continuously positioned optimally so as to ensure both that the user of the seat is comfortable, and that said user is protected from any frontal impacts to which the vehicle might be subjected. In particular, when the back of the seat is tilted backwards to the maximum extent, the support member is raised to the maximum extent, and thus offers the most effective protection possible for preventing the passenger in the seat from being thrown forwards by slipping under the lap segment of the seatbelt that said passenger is wearing.
In preferred embodiments of the invention, any of the following provisions may optionally be used:
the coupling device connects the back of the seat to the support member;
the support member is carried by two side arms pivotally mounted on the framework of the seat proper on either side of said seat proper to pivot about a transverse horizontal axis of rotation, the coupling device comprising two links, each of which is pivotally mounted on the seat back and on one of said side arms, the links being disposed so that the seat back pivoting backwards raises the support member and so that the seat back pivoting forwards lowers said support member;
each side arm extends forwards from the axis of rotation of said side arm to the support member, and is provided with a lever arm that extends downwards from said axis of rotation of the side arm, said lever arm being connected pivotally to one of the links and said link also being connected pivotally to the seat back below the axis of rotation of said seat back; and
the support member comprises a support plate which extends transversely under the padding of the seat proper in the vicinity of the front of said seat proper.